The development of cell culture-based technologies as an alternative to the traditional egg-based production systems for the manufacture of viral vaccines likely appears as the most rapid and most promising solution to overcome drawbacks and constraints associated with egg-based traditional systems. Commercial productions of viral vaccines typically require large quantities of virus as an antigen source. However, the egg-based process is vulnerable due to the varying biological quality of eggs and it lacks flexibility because of the logistic problems due to non-availability of large quantities of suitable eggs.
Cell culture systems appear as a suitable alternate mode of vaccine preparation, simpler, flexible, and consistent, allowing to improve possibilities of up-scaling vaccine production capacities and thus to reach large quantities of virus, if needed. For example, in response to a natural pandemic threat or a to a terrorist attack.
However, efficient vaccine production requires the growth of large scale quantities of virus produced in high yields from a host system. The cultivation conditions under which a virus is grown is of great significance with respect to achieving an acceptable high yield of the virus. Thus, in order to maximise the yield of the desired virus, both the system and the cultivation conditions must be adapted specifically to provide an environment which is advantageous for the production of the desired virus which is suitable for large scale production. One way is to improve the cell specific productivity, for example, by improving the culture medium, or increasing the cell density. Due to the fact that, after production, the cell culture-produced virus must be recovered from the cell culture and purified, another way to improve virus yield is to limit the virus material loss occurring along the different purification steps. Therefore, a need remains for providing alternative and improved methods to produce viruses with an increased virus yield. The method according to the present invention provides a better virus yield over the methods known in the art.